Growing method of large-size flaky sapphire crystals

Abstract

The invention relates to a manufacture technology of sapphire crystals, in particular to a growing method of large-size flaky sapphire crystals. A crystal growing process of the method is carried out in a single-crystal growing furnace internally provided with a crucible and a guide mould, wherein the crystal growing process sequentially comprises the following steps of: sapphire raw material heating, seeding, shouldering, constant-diameter lifting and cooling. The single-crystal growing furnace is internally provided with a protective gas inlet and outlet system capable of introducing and exhausting protective gas and a pressure control system capable of controlling the pressure in the furnace, wherein the protective gas is introduced into the furnace in the steps of sapphire raw material heating, seeding, shouldering and constant-diameter lifting and is formed into flowing gas in the furnace through the protective gas inlet and outlet system, and the gas inlet flow of the protective gas is 0.1-50slpm; and meanwhile, the pressure in the furnace is controlled to be 100pa-90kpa through the pressure control system. The method can be directly used for growing the flaky sapphire crystals with a larger size and has simple manufacture procedure, high material utilization ratio and low manufacture cost.

Description

technical field [0001] The invention relates to a manufacturing technology of sapphire crystals, in particular to a method for growing large-size flaky sapphire crystals. Background technique [0002] Sapphire (α-alumina) crystal material is a colorless and transparent single crystal material. Because sapphire crystal has a similar structure to gallium nitride, has a similar thermal expansion coefficient to silicon, and has good UV resistance, it is widely used in LEDs, SOS integrated circuits, and satellite space technology. [0003] Sapphire crystals have good transmission performance in the spectral range from visible light to 5.6um and are used as optical window materials for many measurement and analysis instruments. The anisotropy of sapphire crystal is applied to waveguide laser cavity, surface acoustic wave filter, delay line, ultrasonic transmission element; the hardness of sapphire crystal (Mohs degree 9) is second only to diamond, and it has high hardness and str...

AI Technical Summary

Problems solved by technology

Among the above methods, the flame method cannot grow single crystals with a diameter larger than 50mm due to the large temperature gradient, and the defects and internal stress values ​​of the crystals are relatively high, so the scope of application is greatly limited.

Large-sized sapphire crystals can be grown by methods such as pulling method, kyropoulos method, heat exchange method, and guided temperature gradient method, but they need to go through a series of heavy mechanical processing such as high hardness cutting, molding, and grinding before they can be made into suitable crystals. The shape and size of the crystal are complex, the process is more complicated; the cost is high and time-consuming; the utilization rate of crystal materials is low, the work efficiency is not high, and the cost remains high